and so all this energy you're pping in, all that energy, that energy is going into mass. and how much? given by this relationship. so at the end of the tube, you'll have more mass than you had when you started. because you're energizing it all the time. and as you push things, push things, some people will say w come you can't go faster than the speed of light? well, to go faster than the speed of light, if you gotta push, you gotta push, you gotta push, when you wanna accelerate something, there are two factors involved. some of you people know what the two factors involved are. if someone said to y, hey, you, you're a physics type, huh? i undersnd that acceleration involves two ideas. what are those ideas? and you would y how hard you push, force, compared to how much inertia you have, mass, isn't that right? so force per mass. now as you're pushing faster and faster and faster and the mass becomes more and more and more, what happens at the speed of light? at the speed of light, what would the mass be? see this little piece of chalk. what's the mass of this piece of ch